1. Field of the Invention
The present invention relates to a gas flow safety assembly to be connected in line between a main gas distribution line and an internal distribution system of a particular facility being supplied so as to provide a safe, secure and efficient manner of ensuring that gas flow, during overpressure or underpressure flow situations, is not maintained to the internal distribution system, while also ensuring that gas flow will be re-initiated to the internal distribution system only when the gas flow pressure has been returned to an acceptable/normal level and when affirmative steps are taken to reset the gas flow subsequent to the determination that a safe operating conditions has been established at the appliance(s) which uses the gas.
2. Description of the Related Art
Generally, most facilities, such as a home or work place, which utilize a gas, such as natural gas, from a general gas supply source are connected at a single point with a main distribution line that is carrying the supply of gas to the facility. Further, because many gas users require different amounts of gas, often at different flow rates or pressures, the gas supply is often provided at maximum levels and is specifically regulated at the single connection with the main distribution line to meet the needs of the user. Once regulated, the pressurized gas is distributed to the various appliances that need it through the internal gas distribution system. Because, however, all of the internal appliances which utilize the gas are essentially connected with one anther, malfunctions or hazardous conditions that affect one appliance will affect all appliances. Also, because the appliances are often located at various points throughout the facility, it is difficult to ensure that al appliances are off, and/or to effect an immediate shut off of gas to all of the appliances as each will generally include their own shut off valve.
Along these lines, an all to frequent occurrence associated with the supply of gas is the temporary shutdown of gas flow by the gas supplier to the consumers. Generally, the flow stoppage becomes necessary due to blockages or ruptures of the main supply line and/or the occurrence of potentially hazardous leaks. Accordingly, when such a shut off is necessary, an underpressure situation wherein insufficient pressure is flowing to the consumer's facility and appliances, or wherein gas pressure is completely discontinued, generally occurs. In these circumstances, the gas consumers are instructed to immediately and completely shutdown all appliances which may utilize the gas and await the return of normal gas pressure before reactivating any of the appliances. Specifically, when the gas provider is seeking to identify the source of a leak or rupture, it necessary to have a completely sealed environment, and the quicker that the closed/sealed environment is achieved, the quicker the leakage or rupture is located. Further, when gas flow supply pressure is reduced individuals utilizing the gas consuming appliances tend to open the gas flow valves at the appliance significantly to check for any gas flow or to increase the permitted gas flow to the appliance and maximize the benefits of the little or no gas pressure they do have. Unfortunately, however, this opening of the valves can be quite hazardous when normal gas flow is reinitiated because a rush of gas can result to the completely opened, lit appliances, resulting in a flash flame, or a significant gas leak can occur through an appliance that has been inadvertently left in a gas flowing orientation.
In addition to the dangerous conditions that an underpressure situation provides to the consumer, those situations also result in a great expense to the gas company who is aware of those dangers. In fact, in most circumstances wherein the gas company must shut down gas flow, even temporarily, an extensive and time consuming check of individual facilities must be performed to ensure that all appliances in those facilities are turned off and that the gas flow to those appliances is maintained off until normal gas pressure is restored.
Additionally, in circumstances where there is a gas flow malfunction in the main service line, where some of the internal appliances or the internal distribution system of the facility are malfunctioning, or when the venting systems of the gas distribution system are malfunctioning, an overpressure flow situation can easily occur. In particular, overpressure situations generally involve a substantially increased pressure flow burst or buildup. Not only is this pressure burst/buildup wasteful, as far as gas which is lost and unused, but it can also create a serious hazard when specific appliances are turned on and ignited expecting only normal gas flows.
Accordingly, it would be highly beneficial to provide a safety assembly which will immediately and automatically terminate gas flow into the internal distribution system of a facility, and hence into each of the appliances located therein, upon a gas flow pressure drop below minimum acceptable levels or above maximum acceptable levels, and which requires specific, affirmative user resetting in order to reinitiate the flow of gas. Further, it would be beneficial to ensure that gas flow in an underpressure situation be re-initiated or reset only when the gas flow pressure has increase back to normal levels, and that gas flow in an over pressure situation be re-initiated or reset only when the system is returned to a normal pressures state, but also when there is sufficient gas flow pressure so as to not be too low. Finally, it would beneficial to provide a safety device which permits for quick and immediate shut down of gas flow to a facility without extensive manipulation, and actuation of various valves and controllers, while ensuring that gas flow is reinitiated only when appropriate operating conditions are reattained.